1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. In addition, the present invention relates to a process, a machine, manufacture, or a composition of matter. In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a driving method thereof, or a manufacturing method thereof. Specifically, one embodiment of the present invention relates to a display device and a manufacturing method thereof.
2. Description of the Related Art
In recent years, liquid crystal has been used for a variety of devices; in particular, a liquid crystal display device (liquid crystal display) having features of thinness and lightness has been used for displays in a wide range of fields.
As a method for applying an electric field to a liquid crystal molecule included in a liquid crystal display device, a vertical electric field mode and a horizontal electric field mode can be given. As a horizontal electric field mode of a liquid crystal display panel, there are an in-plane switching (IPS) mode in which a pixel electrode and a common electrode are formed on the same insulating film and a fringe field switching (FFS) mode in which a pixel electrode and a common electrode overlap with each other with an insulating film provided therebetween.
A liquid crystal display device of an FFS mode has a slit-shaped opening portion in a pixel electrode, and alignment of liquid crystal molecules is controlled by applying an electric field generated between the pixel electrode and a common electrode in the opening portion to the liquid crystal molecules.
The liquid crystal display device of an FFS mode has a high aperture ratio, a wide viewing angle, and an effect of improving an image contrast, and has been widely used recently (see Patent Document 1).